Receiver/dryer and method of assembly

ABSTRACT

A receiver/dryer (10) includes a canister (12) with a cylindrical sidewall (13), an integral lower end (14), and an open upper end (16). A pick-up tube (18) is disposed centrally within the canister. According to one aspect, the lower end (19) of the pick-up tube has a wedged-shape and which is supported by the lower end of the canister. The upper end (20) of the pick-up tube has an annular groove (21) which carries an O-ring seal (22). A lower baffle (23) and lower filter pad (40) are received over the pick-up tube with the lower baffle having a tight slip-fit therewith; loose desiccant (24) is introduced into the canister and supported by the lower baffle and filter pad; and then an upper filter pad (50) and upper baffle (44) are received over the pick-up tube, with the upper baffle having a slip-fit therewith. An upper end cap (60) is then secured to the open end of the canister, with the pick-up tube being received within an outlet passage (64) in the upper end cap and a fluid-tight seal being provided between the pick-up tube (70) and the end cap by the O-ring seal. According to another aspect, a desiccant tube is disposed in fluid-tight relation around the pick-up tube and extends between the lower baffle and the upper baffle. The lower baffle has a fluid-tight fit with the desiccant tube, and preferably has an annular bead (72) and annular flange (74) on the desiccant tube retaining the baffle to the tube. In this further aspect, the pick-up tube can be connected off-center to the end cap, and then bent or curved so as to be aligned with the desiccant tube. In either aspect, the desiccant material can be loose fill, which reduces the over-all cost of the receiver/dryer.

This application is based on Provisional application No. 60/022,832filed Jul. 31, 1996.

FIELD OF THE INVENTION

The present invention relates generally to receiver/dryers forrefrigeration and air conditioning systems, and methods for assemblingsuch receiver/dryers.

BACKGROUND OF THE INVENTION

A receiver/dryer is a common component of a refrigeration or airconditioning system, and receives excess refrigerant in the coolingcycle, separates vapor refrigerant from liquid refrigerant, and removeswater and particulate matter.

One type of receiver/dryer includes a cylindrical canister with inletand outlet fittings at one end which allow refrigerant to flow into andout of the canister. One of the fittings (typically the outlet fitting)is connected at its internal end to a pick-up tube, which extendsdownwardly through the canister to the lower end. Layers of filters anddesiccant material surround the pick-up tube along its length.Refrigerant is directed into the inlet fitting and flows through thefilter pads and desiccant material to the bottom of the canister. Thefilter pads and desiccant material remove particles and other impuritiesfrom the refrigerant. The refrigerant then flows upwardly through thepick-up tube to the outlet fitting.

One type of desiccant material for such a receiver/dryer is provided ina fabric bag which retains the desiccant and allows the desiccant to beeasily located within the canister during assembly. Designs for suchdesiccant bags include a pouch, saddle-bag or donut-shape, and are shownfor example in Searfoss, et al., U.S. Pat. No. 5,245,842; Kish, et al.,U.S. Pat. No. 4,496,378; Wintersteen, et al., U.S. Pat. No. 5,179,780;Shiina, et al., U.S. Pat. No. 5,191,775; and Mosher, et al., U.S. Pat.No. 5,215,660.

A desiccant bag particularly lends itself to easy assembly within areceiver/dryer which has the lower end wall of the canister formed inone piece (or at least integrally) with the side walls of the canister.The lower end wall can be formed by drawing, impacting or spin-formingthe sidewalls of the canister closed at one end. While all subsequentcomponents must be inserted from the open upper end of the canister,such canisters have been found to be cost-effective to produce forcertain applications.

In a receiver/dryer with an integral lower end wall, the desiccant bag,and any filters, baffles, etc., are introduced into the canister fromthe upper end. The pick-up tube is then pre-assembled with the upper endcap and inserted into the canister. The desiccant bag could also beinitially located around the pick-up tube and introduced into thecanister at the same time as the pick-up tube. The upper end cap is thenfluidly sealed to the sidewalls of the canister by appropriate means,e.g., welding, brazing, soldering, etc., and the receiver/dryer isconnected within the refrigeration system. By using such a desiccantbag, it is relatively easy to introduce the pick-up tube down throughthe canister as the desiccant remains contained within the bag and doesnot randomly disperse throughout the canister.

While the above receiver/dryers have received some acceptance in themarketplace, enclosing the desiccant in a bag adds labor and materialcost to the receiver/dryer, and does not allow flexibility in using thebags in a wide variety of applications. For example, each bag isdesigned for a specific application and has a predetermined volume,porosity, material and desiccant composition, etc. To change thestructure, material or composition of the desiccant bag for otherapplications, new bags typically must be manufactured. This can requiretooling changes and ordering of new fabric and desiccant material, allof which can be time-consuming and expensive. Stocks of different sizesand types of desiccant bags also typically have to be kept on hand whichcan increase storage and inventory costs, and hence the over-all cost ofthe receiver/dryer.

As such, applicants believe that it would be desirable to use loosedesiccant material for the receiver/dryer in certain applications. Suchloose desiccant material can be less expensive to purchase and is easilyadaptable to a wide variety of applications (i.e., does not haverestrictions as to form or composition). The desiccant can just be added(poured) into the canister in the desired amount, with no additionallabor or material costs.

In using loose desiccant material, however, it can be difficult toassemble the receiver/dryer when the canister is formed with an integrallower end. To begin with, the pick-up tube is typically pre-assembledwith the upper end cap and secured thereto by, e.g., coining, crimping,or swaging, so as to ensure a fluid-tight connection. In so doing, thedesiccant must be introduced into the canister before the pick-up tubeis inserted, or else the end cap blocks the easy filling of thecanister, as well as the introduction of subsequent components such asthe upper baffle and filter pad. However, it can be difficult (or evenimpossible) to introduce the pick-up tube into the canister when theloose desiccant is randomly dispersed in the canister. Specifically, itis not desirable to force the pick-up tube through a loose bed ofdesiccant material. The desiccant can also flow through the pick-up tubeopening in the lower baffle before the pick-up tube is inserted into thecanister, and thus enter the lower, quiescent area of thereceiver/dryer.

In addition, applicants believe that the pick-up tube has heretoforebeen formed essentially straight and vertical to allow the pick-up tubeto be inserted through the various baffles and filter pads in thecanister. In so doing, the upper end of the pick-up tube is necessarilyconnected to the upper end cap along the center-line of the canister.However, in some applications it can be desirable to mount a pluralityof components to the top surface of the end cap. If the pick-up tubemust be connected along the center-line, this can limit the ability toattach additional exterior components to the end cap, and hence limitthe usefulness of the receiver/dryer for some applications. While it isknown to form the outlet passage off-center on the end cap, cross holesmust then be drilled transversely through the end cap to connect theoutlet passage to the pick-up tube, which increases machining steps,labor costs, and wasted material.

As such, applicants believe there is a demand in the marketplace for areceiver/dryer which, although it includes an integral lower end, issimple to assemble and is particularly suited to accepting loosedesiccant material to reduce the over-all cost of the receiver/dryer.Applicants also believe there is a demand for a receiver/dryer whichallows for an off-center connection between the pick-up tube and the endcap such that there is flexibility in attaching exterior components tothe end cap.

SUMMARY OF THE PRESENT INVENTION

The present invention provides a new and unique receiver/dryer, andmethod of assembly for such a dryer, which allows loose desiccant to befilled from the top of the receiver/dryer. According to one aspect, abent or curved pick-up tube can be used such that an off-centerconnection to the upper end cap can be obtained. The receiver/dryer issimple to assemble, cost-effective to produce, and has flexibility inattaching exterior components to the upper end cap of thereceiver/dryer.

According to the present invention, the receiver/dryer preferably has anend cap or wall formed in one piece with the sidewall of the canister.The canister can be drawn, impacted, spun, or otherwise formed with theclosed lower end. A pick-up tube is then inserted through the open upperend of the canister. According to one aspect of the present invention,the bottom end of the pick-up tube has a notched or wedged-shape designand rests against the lower, closed end of the canister. The notchallows refrigerant to flow into (or out of) the pick-up tube. The upperend of the pick-up tube has an outer annular groove or channel whichreceives an O-ring seal.

A lower baffle and filter pad, both of which have a central opening, arethen located over the pick-up tube and are disposed toward the lower,closed end of the canister. The baffle preferably has a slip-fit withthe pick-up tube, and a slip-fit with the interior sidewall of thecanister, and can be staked to the pick-up tube and/or the canister, ifnecessary or desirable. Preferably, the periphery of the baffle issupported by a tapered shoulder in the canister, which is formed betweenthe sidewall and the lower, closed end of the canister and createsessentially a fluid-tight fit. Loose desiccant is then poured into thecanister in the desired amount, and is supported by the lower baffle andfilter pad.

An upper filter pad and baffle, both of which also have a centralopening, are then received over the pick-up tube, and support the upperend of the desiccant material. The upper baffle also preferably has aslip-fit with the pick-up tube and the canister, and can be staked tothe pick-up tube and/or the canister. The upper and lower baffles (andfilter pads), prevent vibration or movement of the desiccant material.

An upper end cap, with inlet and outlet passages, is then located overthe upper, open end of the canister. The upper end of the pick-up tubeis received within the outlet passage of the end cap, and preferably hasa slip-fit therewith. The support of the pick-up tube on the lower endof the canister forces the upper end of the tube into the outletpassage. The O-ring on the upper end of the pick-up tube provides afluid-tight seal within the upper end cap. The upper end cap is thensecured to the canister with a fluid-tight seal, such as by brazing,welding, soldering, etc.

According to a further aspect of the present invention, a desiccant tubeis provided around the pick-up tube and has a press-fit, fluid-tightseal therewith. The desiccant tube extends at least between the lowerbaffle and the upper baffle, and is surrounded by the desiccantmaterial. The lower and upper baffles have a slip-fit with the desiccanttube, and can be staked thereto. The lower baffle is preferably retainedbetween an annular bead and an outwardly-projecting flange on the lowerend of the desiccant tube. The bead and flange on the desiccant tube canbe controlled during forming such that one (or both) creates a press-fitwith the pick-up tube when the pick-up tube is later inserted into thedesiccant tube. Alternatively, the lower baffle could be formed inone-piece with the desiccant tube, and the tube could be roll-formed tocreate the press-fit with the pick-up tube.

In this aspect, the desiccant tube with lower baffle and filter pad canbe inserted first into the receiver/dryer canister, and the loosedesiccant can then be poured into the canister with the lower baffle andfilter pad supporting the lower end of the desiccant material. The upperfilter pad and upper baffle can then be located over the desiccant tubeto support the upper end of the desiccant material. The pick-up tube isthen pre-assembled with the upper end cap and inserted through thedesiccant tube. The pick-up tube can be connected to the upper end capsuch as by crimping or coining the pick-up tube to the end cap. In thiscase, the pick-up tube can be spaced from the lower, closed end of thecanister. Alternatively, the pick-up tube can be connected as in thefirst aspect of the invention, i.e., a slip-fit within the outletpassage of the end cap with an O-ring providing a fluid-tight seal.

In this further aspect of the invention, the pick-up tube can be bent orcurved, such that the lower end of the pick-up tube is aligned with thedesiccant tube, but that the upper end is connected in an off-centerrelation to the outlet passage in the end cap. This allows flexibilityin connecting exterior components to the end cap.

In either aspect described above, the present invention provides asimple and cost-effective receiver/dryer and method for assembling sucha receiver/dryer. Loose desiccant material, rather than desiccant bags,can be used with the receiver/dryer, which reduces the over-all cost ofthe receiver/dryer and provides flexibility in tailoring the amount,composition, etc. of desiccant material to the particular application.In addition, an off-center connection to the end cap is provided, whichincreases the flexibility of attaching exterior components to the endcap of the receiver/dryer.

Further features of the present invention will become apparent to thoseskilled in the art upon reviewing the following specification andattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of a receiver/dryer constructedaccording to the principles of the present invention;

FIG. 2 is an enlarged, cross-sectional view of the upper end of thepick-up tube and the upper end cap;

FIG. 3 is a plan view of a baffle for the receiver/dryer of FIG. 1;

FIG. 4 is a cross-sectional view of the baffle taken substantially alongthe plane defined by the lines 4--4 of FIG. 3;

FIG. 5 is a cross-sectional side view of a filter pad for thereceiver/dryer of FIG. 1;

FIG. 6 is a cross-sectional side view of a receiver/dryer constructedaccording to a further aspect of the present invention;

FIG. 7 is an enlarged cross-sectional side view of the receiver/dryer ofFIG. 6, but showing certain components of the receiver/dryer in aninitial stage of assembly; and

FIG. 8 is a cross-sectional side view of a receiver/dryer similar toFIG. 6, but showing a bent or curved pick-up tube.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, and initially to FIGS. 1 and 2, areceiver/dryer constructed according to the principles of the presentinvention is indicated generally at 10. The receiver/dryer includes acylindrical canister 12 having a sidewall 13 with a lower closed end 14and an upper open end 16. Canister 12 is preferably formed fromappropriate material, such as aluminum (type 6061), and the closed lowerend 14 is .preferably formed in one piece with the sidewall such as bydrawing, impacting or spin-forming the lower end of the sidewall. Thelower end 14 could also be welded, brazed, soldered or attached in someother manner to the sidewall 13 such that the lower end wall is at leastintegral (i.e., non-removable) with the sidewall. The canister couldalso be formed from other materials, such as steel. However the presentinvention is particularly suited to aluminum canisters formed inone-piece with a lower end cap or wall. The techniques for formingaluminum (or other metals) by the above methods are known to thoseskilled in the art. In any case, the closing operation preferably formsan annular tapered shoulder 17 between sidewall 13 and lower end 14,which will be explained herein in more detail.

The receiver/dryer 10 includes a pick-up tube 18 which is disposedwithin canister 16 and extends along the central, longitudinal axisthereof. Pick-up tube 18 is also preferably formed from aluminum (type3003) and has a lower downstream end 19 with a wedge or notch-shapedconfiguration. The lower end 19 of pick-up tube 18, and particularly the"point" of the wedge or notch, is disposed against the lower end 14 ofthe canister. The wedge or notched-shaped design allows fluid to enter(or exit) the hollow central bore of the pick-up tube. The upper end 20of the pick-up tube has an annular channel or groove 21 formed by, e.g.,roll-forming, surrounding the tube proximate end 20. Groove 21 has adepth which is sufficient to receive an elastomeric O-ring seal 22, withseal 22 projecting slightly outward from the groove in its natural orrelaxed state.

As shown in FIGS. 1, 3 and 4, the receiver/dryer also includes a loweror downstream annular baffle 23 which supports desiccant material 24.Lower baffle 23 has a flat annular body 25 with an inner annular collaror flange 26 forming a central opening 27, and an outer annular collaror flange 28 extending around the periphery. Both the inner flange 26and outer flange 28 extend downstream from body 25. Outer flange 28preferably closely matches the inner diameter of canister sidewall 13,such that the outer flange is secured with at least a slip-fit(press-fit if possible) to the sidewall. The inner flange 26 alsoclosely matches the outer diameter of the pick-up tube 18, such that theinner flange is also secured with a slip-fit (press-fit if possible) topick-up tube 18. Alternatively, lower baffle 23 could be pre-assembledwith pick-up tube 18 and could be more firmly attached, such as bycoining or crimping the inner flange 26 to the pick-up tube, or byproviding one or more closely-spaced annular beads on the pick-up tubeto retain the baffle at a specific location. The baffle could also beformed without inner and/or outer flanges 26, 28, and have merely theinner diameter and outer diameter of body 25 retain the body between thepick-up tube and canister. In any case, the baffle could be staked tothe pick-up tube and/or the canister, if necessary or desirable, toretain the baffle more securely between these components. Finally, aplurality of perforations or openings, for example as indicated at 36,are formed in the flat body 25 of baffle 23 to allow fluid flowtherethrough. Baffle 23 is formed from an appropriate material, forexample aluminum, using conventional metal-forming techniques such asdies and stamps, or should be known to those skilled in the art.

Against the upstream surface of baffle 23, and extending between innerflange 26 and outer flange 28, is a lower annular filter pad 40. Filterpad 40 includes a central opening 46 which corresponds to the centralopening 27 of baffle 23. Filter pad 40 prevents migration of desiccantmaterial 24 through lower baffle 23, and provides filtration ofrefrigerant flowing therethrough. As shown more particularly in FIG. 4,the lower filter pad preferably has an upstream, more porous (lessdense) layer 42 in contact with the downstream surface of baffle 23, andan downstream, less porous (less dense) layer 44 facing away from baffle23. Filter pad 40 is formed of an appropriate porous material, forexample fiberglass, although lower baffle 23 could also be formed fromsuch a material to filter the refrigerant, in which case the lowerfilter pad might not be necessary.

Desiccant material 24 is preferably a conventional desiccant which isavailable from a number of sources. For example, an appropriatedesiccant material is manufactured by UOP under thetrademarks/designations XH7 and XH9. Other types of desiccant materialcan of course be used, and it is noted that the present invention isprimarily directed toward a "loose-fill" desiccant, that is, a desiccantwhich is not contained within any bag, but is rather in a loose stateand constrained only by the sidewall of the canister and the upper andlower baffles (and filter pads). Such loose-fill desiccant tends to beless expensive than desiccant material which is available in a bag form,although it should be apparent that desiccant in a bag form could ofcourse be used with the present invention, although more expensive. Theamount of desiccant necessary for the receiver/dryer depends on theparticular application and can be easily determined by those skilled inthe art. The present invention has the flexibility to use differentvolumes or compositions of desiccant material in a simple and easymanner by merely filling the canister to the desired level. Thereceiver/dryer is not limited to a particular volume or composition ofdesiccant, and can be used in different applications without having toorder or stock desiccant bags of different volumes, sizes orcomposition.

The upper annular baffle 44 is similar to the lower baffle 23, andincludes a perforated flat body 45 preferably bounded on its inside byan inner annular flange or collar 46 and on its periphery by an outerannular flange or collar 48. The inner and outer flanges 46, 48 againextend downstream from body 45. Baffle 44 could also be formed withoutinner flange 46 and outer flange 48, as with the lower baffle 23. Anupper annular filter pad 54 has a central opening and is providedagainst the upstream surface of baffle 44 to prevent migration ofdesiccant material through the baffle, and for filtration of refrigerantflowing therethrough. Upper baffle 44 and filter pad 54 preferably havethe same configuration and are formed of the same material as lowerbaffle 23 and filter pad 40 illustrated in FIGS. 3-5 to support theupper end of the desiccant material. The outer annular collar 48preferably is secured with at least a slip-fit to the inner diameter ofcanister 12, while the inner annular flange 46 is secured with at leasta slip-fit to the pick-up tube 18. The inner and outer flanges of theupper baffle could also be staked to the pick-up tube and/or thecanister, if necessary or desirable. The upper and lower baffle (andfilter pads) securely hold the desiccant material to prevent undesirablemovement or vibration thereof.

An upper annular end cap 60 encloses the open upper end 16 of canister12. End cap 60 preferably has a substantially flat exterior surface 62with mounting holes 63 for mounting exterior components. An outletpassage 64 and an inlet passage 66 extend through the end cap. In thisaspect of the invention, the outlet passage 64 is preferably disposedabout the longitudinal center-line of the canister and receives theupper end 20 of the pick-up tube when assembled. The outlet passage andinlet passage could also be reversed in particular applications, i.e.,the inlet passage could be connected to the pick-up tube, and thepresent invention is not intended to be limited to either passage beingfor "inlet" or "outlet" refrigerant flow. However, in most applications,the outlet passage will be connected to the pick-up tube to directrefrigerant out of the lower end of the receiver/dryer. In any case, thepick-up tube 18 is received with a slip-fit within passage 64. TheO-ring 22 at the end of the tube provides a fluid-tight seal between thepick-up tube and the end cap when the end cap is assembled to thecanister, without the need for any mechanical sealing (such as bycoining, crimping, etc.) to the end cap. The end cap is then fluidlysealed to the sidewall 13 of the canister such as by welding, brazing,soldering, etc., such as at 70.

In assembling the receiver/dryer, canister 12 is initially provided withlower end cap 14 formed integrally therewith, and preferably in onepiece therewith. Pick-up tube 18 is inserted within canister 12, withthe lower end 19 of the pick-up tube contacting the closed, lower end 14of the canister. Next, the lower baffle 23 and lower filter pad 40 arereceived about the pick-up tube and slid down toward the lower end 19.The lower baffle 23 is attached to the pick-up tube by the slip-fittherewith, or alternatively, as described above, could be pre-assembledwith the pick-up tube and attached thereto such as by coining orcrimping, or by one or more annular beads. The lower baffle 23 ispreferably supported at its periphery by the inwardly-tapered shoulder17 formed at the intersection of canister 13 and lower end 14. Thecontact between the periphery of the lower baffle and the shouldercreates essentially a fluid-tight seal with the canister. The lowersurface of baffle 23 faces the lower end of the receiver dryer and,together with the lower end, defmes a quiescent chamber 67.

Next, the loose desiccant material 24 is loaded (e.g., poured) throughthe open end of canister 12 to fill an appropriate portion of thecanister. The lower baffle 23 supports the lower end of the desiccantmaterial while lower filter pad 40 prevents the desiccant from passingthrough the openings in the lower baffle.

Next, the upper filter pad 50 and upper baffle 44 are received about thepick-up tube 18 and slid down to support the upper end of the desiccantmaterial. The upper filter pad 50 prevents desiccant from passingthrough the openings in the upper baffle, while both the upper and lowerbaffles (and filter pads) prevent undesirable movement or vibration ofthe desiccant material.

Upper end cap 60 is then located over the open upper end 16 of thecanister, with the upper end 20 of the pick-up tube 18 being receivedwithin outlet passage 64. By supporting the lower end 19 of the pick-uptube 18 against the lower end 14 of the canister, the pick-up tube isforced into passage 64, with the O-ring 22 providing a fluid-tight sealtherebetween. The fluid-tight seal created by O-ring 22 can be providedanywhere along the length of the passage 64, which allows the tolerancesbetween these components to be greater. The upper end cap is thenfluidly-sealed to the canister in an appropriate manner, such as bybrazing, welding, soldering, etc. The outlet and inlet passages 64, 66are then fluidly connected within the refrigeration system in aconventional manner, and refrigerant is introduced (typically from thecondenser) through the inlet passage and down through the baffles,filter pads and desiccant material to the quiescent chamber to removewater and particulate matter. Refrigerant is then drawn upward throughpick-up tube and directed through the outlet passage to therefrigeration system (typically to the expansion device).

According to a second aspect of the present invention, as illustrated inFIGS. 6 and 7, the receiver/dryer 10 can include a desiccant tube 70co-axial with and received around the pick-up tube 18, with thedesiccant tube 70 extending between lower baffle 23 and upper baffle 44.Lower baffle 23 has at least a slip-fit (press-fit if possible) withdesiccant tube 70. It is preferred that desiccant tube 70 have anannular bead 72 and an outwardly-turned annular flange 74 at the lowerend of the desiccant tube. Bead 72 and flange 74 are spaced closetogether and contact opposite sides of lower baffle 23. Specifically,bead 72 contacts the upper, radially-extending end surface of flange 28on baffle 23, while flange 74 on desiccant tube 70 follows the curve offlange 28 and supports body 25 along the inner diameter on the lower,upstream surface of the baffle, thus securing the baffle to thedesiccant tube.

The inner diameter of the desiccant tube can be easily and closelycontrolled when the bead and/or flange are formed on the desiccant tube.End forming or flange roll forming machines can create the bead orflange and at the same time narrow the inner diameter of the tube at thelocation of the bead or flange. When the pick-up tube is inserted, apress-fit, fluid-tight seal is provided between the desiccant tube andthe pick-up tube at the location of the bead or flange.

Alternatively, the inner flange 26 on the lower baffle could beroll-formed into engagement with the desiccant tube 70, or aclosely-spaced pair of beads could be formed in the desiccant tube,rather than a bead and flange. Desiccant tube 70 and lower baffle 23could also be formed together as one piece. In this case, the desiccanttube could just be roll-formed, with the inner diameter closelycontrolled so as to provide a press-fit with the pick-up tube when thepick-up tube is later inserted into the desiccant tube. In any case,end-forming, flange roll forming and roll forming machines which createsuch beads and flanges are conventional machinery and should be known tothose skilled in the art. It should also be noted that the remainder ofthe desiccant tube can be merely a slip-fit with the pick-up tube, whichrelieves tolerances and reduces fabrication costs of the desiccant tubeand pick-up tube.

According to this further aspect of the invention, lower baffle 23 anddesiccant tube 70 are preferably inserted first into canister 12. Lowerbaffle 23 is preferably supported at its periphery by the shoulder 17formed between canister sidewall 13 and the lower end 14. Lower filterpad 40 is then assembled with lower baffle 23. Desiccant 24 is thenintroduced into the canister and supported at its lower end by baffle 23(and lower filter pad 40). The upper filter pad 50 and upper baffle 44are then introduced into the canister and received over desiccant tube70 to support the other end of the desiccant material 24. The upperbaffle 44 has a slip-fit with desiccant tube 70 and can also be stakedto the desiccant tube, if necessary or desirable. With the tight-fitbetween lower baffle 23 and desiccant tube 70 (or these components beingformed in one piece), and a press-fit between desiccant tube 70 andpick-up tube 18, essentially a fluid-tight seal is provided entirelyacross the lower baffle and the pick-up tube without any additionalsealing components such as gaskets, rings, etc. As in the first aspect,the outer periphery of lower baffle 23, has at least a slip-fit(press-fit if possible) with the canister 12, while upper baffle 44 hasa slip-fit with canister 12.

Pick-up tube 18 can then be pre-assembled with end cap 60 and insertedthrough desiccant tube 70. Preferably, the pick-up tube has a bead 78 atits upper end which is received within a collar 80 surrounding passage64. The collar is then coined or crimped around the bead to provide afluid-tight connection between the pick-up tube and the upper end cap.An O-ring (not shown) can be provided within the collar (at the upper orlower side of bead 79) to improve the fluid-tight connection. Inaddition, as illustrated in FIG. 8, the pick-up tube 18 can be connectedoff-center to the end cap 60, and then bent or curved along the centerline of the canister to be aligned with the desiccant tube 70. Thisprovides flexibility in locating the outlet passage 64 in an off-centerrelation on the end cap and therefore in mounting additional componentsto the exterior surface of the end cap. The end cap 60 is then securedto canister sidewall 13 as described previously, such as by welding,brazing, soldering, etc.

It is noted that if pick-up tube 18 is secured to end cap 60 in theabove manner (i.e., by crimping or coining), then the lower end 19 ofthe pick-up tube can be spaced from the lower end 14 of the canister.This is because the upper end of the pick-up tube is attached to the endcap, which does not occur in the first aspect of the present invention.Alternatively if the pick-up tube can be secured to the upper end cap asin the first aspect, i.e., by a slip-fit with an O-ring providing thefluid-tight seal. In this case, the pick-up tube can extend downward andbe supported by the lower end 14 of the canister such that the upper endof the pick-up tube is pushed up through the outlet passage in the upperend cap when assembled.

Thus, as described above, the present invention provides a new andunique receiver/dryer and method for assembling such a receiver/dryerwhich is simple and cost-effective to manufacture. The receiver/dryer isparticularly useful with loose desiccant which can be used even thoughthe receiver/dryer has an integral lower end and must be loaded from thetop. The receiver/dryer also has flexibility in being able to easilyaccommodate different volumes or compositions of desiccant material fordifferent applications, and for allowing for the off-center connectionof the pick-up tube to the end cap, without additional labor, materialor costs.

The principles, preferred embodiments and modes of operation of thepresent invention have been described in the foregoing specification.The invention which is intended to be protected herein should not,however, be construed as limited to the particular form described as itis to be regarded as illustrative rather than restrictive. Variationsand changes may be made by those skilled in the art without departingfrom the scope and spirit of the invention as set forth in the appendedclaims.

What is claimed is:
 1. A receiver/dryer, comprising:a canister having alongitudinally-extending cylindrical sidewall, a first end cap integralwith one end of said sidewall and an opening at another end of saidsidewall; a pick-up tube extending longitudinally within said canisterwith a first end of said pick-up tube proximate said first end cap and asecond end of said pick-up tube spaced remotely from said first end cap;a desiccant tube disposed in surrounding, fluid-tight relation to saidpick-up tube, said desiccant tube and said pick-up tube havingcooperating, mechanically-deformed structure creating a fluid-tight,press-fit seal between said pick-up tube and said desiccant tube; afirst annular baffle having a peripheral dimension closely matching aninterior dimension of said sidewall and fluidly-sealed to said desiccanttube, disposed in said canister proximate said first end cap; a secondannular baffle having a peripheral dimension closely matching theinterior dimension of said sidewall and a central opening receiving saiddesiccant tube, said second baffle being disposed in said canister andreceived about said desiccant tube remotely from said first end cap;loose desiccant material disposed in said canister and surrounding saiddesiccant tube between said first and second baffles; and a second endcap having first and second passages extending through the second endcap to allow refrigerant to flow into and out of said canister, saidsecond end cap enclosing said other end of said sidewall and receivingsaid second end of said pick-up tube in one of said passages in afluid-tight relation therewith.
 2. The receiver/dryer as in claim 1,wherein said first baffle has a central opening receiving said desiccanttube, and is at least slip-fit with said desiccant tube.
 3. Thereceiver/ dryer as in claim 2, wherein said desiccant tube has anannular bead retaining said first baffle on said desiccant tube.
 4. Thereceiver/dryer as in claim 3, wherein said desiccant tube further has anannular flange, said annular flange and said annular bead beingspaced-apart along said desiccant tube and contacting opposite surfacesof said first baffle to retain said first baffle on said desiccant tube.5. The receiver/dryer as in claim 4, wherein one of said annular beadand annular flange has an inner diameter which is press-fit with saidpick-up tube, the remainder of said desiccant tube being slip-fit withsaid pick-up tube.
 6. The receiver/dryer as in claim 5, wherein saidfirst baffle includes an annular, radially-extending body with a firstsurface and a collar surrounding said central opening in said firstbaffle and extending longitudinally in the canister away from a secondsurface of said body, said collar having a radially-extending annularend surface, said annular bead of said desiccant tube engaging saidannular end surface of the desiccant tube, and said annular flangeengaging said first surface of said body to secure said first baffle tosaid desiccant tube.
 7. The receiver/dryer as in claim 6, wherein saidfirst baffle is secured to said sidewall.
 8. The receiver/dryer as inclaim 7, wherein said second baffle is secured to said desiccant tubeand to said sidewall.
 9. The receiver/dryer as in claim 7, wherein saidfirst baffle and said sidewall are slip-fit together.
 10. Thereceiver/dryer as in claim 9, wherein said second baffle is slip-fitwith said desiccant tube and with said sidewall.
 11. The receiver/dryeras in claim 1, wherein said first end cap is formed in one piece withsaid sidewall.
 12. The receiver/dryer as in claim 11, wherein saiddesiccant material is supported directly against an interior surface ofsaid canister sidewall.
 13. The receiver/dryer as in claim 1, whereinsaid pick-up tube is co-axial with said desiccant tube along alongitudinal axis of the canister, and then is bent away from thelongitudinal axis and is received in said second end cap at a locationspaced from the longitudinal axis.
 14. The receiver/dryer as in claim 1,further including means for connecting said first baffle to saiddesiccant tube.
 15. The receiver/dryer as in claim 14, wherein saidbaffle is formed as a separate piece from said desiccant tube.
 16. Thereceiver/dryer as in claim 1, wherein said cooperating,mechanically-deformed structure provides a fluid-tight, press-fit sealalong a predetermined portion of the desiccant tube, the remainder ofthe desiccant tube being slip-fit with said pick-up tube.
 17. Areceiver/dryer, comprising:a canister having a longitudinally-extendingcylindrical sidewall, a first end cap integral with one end of saidsidewall and an opening at another end of said sidewall; a pick-up tubeextending longitudinally within said canister with a first end of saidpick-up tube proximate said first end cap and a second end of saidpick-up tube spaced remotely from said first end cap; a desiccant tubedisposed in surrounding, fluid-tight relation to said pick-up tube, saiddesiccant and said pick-up tube having cooperating structure creating afluid-tight seal between said pick-up tube and said desiccant tube, afirst annular baffle having a peripheral dimension closely matching aninterior dimension of said sidewall and fluidly-sealed to said desiccanttube, disposed in said canister proximate said first end cap, saiddesiccant tube having an annular bead and an annular flange, saidannular bead and said annular flange being spaced-apart along saiddesiccant tube and contacting opposite surfaces of said first baffle toretain said first baffle on said desiccant tube; a second annular bafflehaving a peripheral dimension closely matching the interior dimension ofsaid sidewall and a central opening receiving said desiccant tube, saidsecond baffle being disposed in said canister and received about saiddesiccant tube remotely from said first end cap; loose desiccantmaterial disposed in said canister and surrounding said desiccant tubebetween said first and second baffles; and a second end cap having firstand second passages extending through the second end cap to allowrefrigerant to flow into and out of said canister, said second end capenclosing said other end of said sidewall and receiving said second endof said pick-up tube in one of said passages in a fluid-tight relationtherewith.
 18. The receiver/dryer as in claim 17, wherein one of saidannular bead and annular flange has an inner diameter which is press-fitwith said pick-up tube, the remainder of said desiccant tube beingslip-fit with said pick-up tube.
 19. The receiver/dryer as in claim 18,wherein said first baffle includes an annular, radially-extending bodywith a first surface and a collar surrounding said central opening insaid first baffle and extending longitudinally in the canister away froma second surface of said body, said collar having a radially-extendingannular end surface, said annular bead of said desiccant tube engagingsaid annular end surface of the desiccant tube, and said annular flangeengaging said first surface of said body to secure said first baffle tosaid desiccant tube.
 20. The receiver/dryer as in claim 17, wherein saidfirst baffle and said sidewall are slip-fit together, and said secondbaffle is slip-fit with said desiccant tube and with said sidewall. 21.The receiver/dryer as in claim 17, wherein said first end cap is formedin one piece with said sidewall, and said desiccant material is loosefill, said desiccant material being supported directly against aninterior surface of said canister sidewall.
 22. The receiver/dryer as inclaim 17, wherein said pick-up tube is co-axial with said desiccant tubealong a longitudinal axis of the canister, and then is bent away fromthe longitudinal axis and is received in said second end cap at alocation spaced from the longitudinal axis.
 23. A receiver/dryer,comprising:a canister having a longitudinally-extending cylindricalsidewall, a first end cap integral and in one-piece with one end of saidsidewall and an opening at another end of said sidewall; a pick-up tubeextending longitudinally within said canister with a first end of saidpick-up tube proximate said first end cap and a second end of saidpick-up tube spaced remotely from said first end cap; a desiccant tubedisposed in surrounding, fluid-tight relation to said pick-up tube, saiddesiccant tube and said pick-up tube having cooperating structurecreating a press fit fluid-tight seal between said pick-up tube and saiddesiccant tube; first annular baffle having a peripheral dimensionclosely matching an interior dimension of said sidewall andfluidly-sealed to said desiccant tube, disposed in said canisterproximate said first end cap; a second annular baffle having aperipheral dimension closely matching the interior dimension of saidsidewall and a central opening receiving said desiccant tube, saidsecond baffle being disposed in said canister and received about saiddesiccant tube remotely from said first end cap; loose desiccantmaterial disposed in said canister and surrounding said desiccant tubebetween said first and second baffles, said desiccant material supporteddirectly against an interior surface of the canister sidewall; and asecond end cap having first and second passages extending through thesecond end cap to allow refrigerant to flow into and out of saidcanister, said second end cap connected to said other end of saidsidewall and receiving said second end of said pick-up tube in one ofsaid passages in a fluid-tight relation therewith.